▶ Watch Video: International search crews race to find submersible that disappeared on Titanic wreckage voyage

A deep-sea robot found a “debris field” while searching for a sub that went missing while carrying five people to the wreckage of the Titanic, the U.S. Coast Guard said Thursday. Experts were evaluating the discovery by the ROV, or remotely operated vehicle.

“A debris field was discovered within the search area by an ROV near the Titanic,” officials said.

Coast Guard officials were expected to discuss the findings during a news conference Thursday afternoon.

In addition to the underwater robots, search planes and ships have been deployed to the northern Atlantic Ocean in the hopes of finding the lost 21-foot sub Titan.

The Coast Guard said Thursday morning one of the robots started searching for sub on the sea floor. Another robot was also added to the search effort Thursday.

The sub launched into the Atlantic from a Canadian research vessel Sunday morning, and the vessel lost contact with the Titan an hour and 45 minutes into the dive.

Officials previously said the sub had a limited amount of oxygen on board that could have lasted 96 hours, or into Thursday morning.

On Wednesday, Coast Guard Capt. Jamie Frederick said the remaining oxygen was “a dialogue that’s happening” but not the only detail being considered in continuing the search.

The co-founder of the company that owns the sub, OceanGate, said Thursday was “a critical day” in the search. In a statement on Facebook, Guillermo Sohnlein said the group may have extended their life support supplies by “relaxing as much as possible.”

“I firmly believe that the time window available for their rescue is longer than what most people think,” Sohnlein said.